Ce travail de thèse est principalement dédié à la mise en forme et à l’utilisation de nano-objets unidimensionnels comme matériaux d’électrodes transparentes. Les nanofils d’argent font partie des candidats les plus prometteurs pour le remplacement de l’oxyde d’indium-étain, actuellement le plus répandu dans les dispositifs commerciaux. La forte instabilité des nanofils d’argent à l’oxydation est néanmoins un problème critique puisque les électrodes deviennent moins performantes en peu de temps. En premier lieu, la triphénylphosphine a été utilisée comme agent inhibant l’oxydation. Contrairement aux électrodes non modifiées, celles-ci sont stables pendant plus de trois mois. Une deuxième partie est consacrée à l’utilisation de l’électrofilage pour élaborer des électrodes transparentes à base de nanofibres de matériaux conducteurs (nanofibres de cuivre, nanotubes de carbone, oxyde de graphène réduit). Enfin, une dernière partie concerne l’étude des propriétés mécaniques de nanofibres d’alcool polyvinylique par l’écoulement d’un fluide porteur dans une constriction réalisée en impression 3D. Cette méthode permet une analyse et une évaluation simple et rapide de la contrainte à la rupture des nanofibres, propriété difficilement accessible par des mesures mécaniques traditionnelles. / This PhD work deals mainly with the high scale organization and use of unidimensional nano-objects for making transparent electrodes. Among the candidates of choice for the replacement of indium tinoxide, the main material used in commercial devices, silver nanowires (Ag NW) are among the most promising. However, the tendency of silver nanowires to be quickly oxidized can severely affect their performances. Firstly, this drawback is circumvented through the use of triphenylphosphine (PPh3)as a protective agent. Unlike bare Ag NW electrodes, the PPh3 modified Ag NW electrodes are stable over three months. A second part is dedicated to the production of transparent electrodes via the electrospinning technique. Materials such as copper nanofibers, carbon nanotubes and reduced graphene oxide are investigated. The last part of the manuscript deals with the measurement of the mechanical properties of poly(vinyl alcohol) (PVA) nanofibers. To do so, the flowing of a fluid in a3D-printed constriction is used. Usually determined with difficulty, the fracture strength of the nanofibers can be evaluated quickly at ease.

With industries aiming at higher efficiencies, lightweight parts, and easier manufacturability there has been a recent trend of replacing the metallic materials with polymeric materials and its composites. Particularly in the automotive industry, there is a demand of replacing metallic material of bushes and bearings with polymer based materials (PBM). For these heavy performance requirements (as in automobiles), the commonly used industrial polymers like Acetal and Nylon fail to provide good mechanical and tribological performance. High-performance polymer like Polyphenylene Sulfide (PPS) is a relatively newer material and shows a potential of being a PBM alternative for metallic bearings in automobiles if their tribological performance can be improved.  One of the ways of improving the tribological performance of the polymer is by the addition of filler material, hence making a polymer composite. In this study, we used Short Carbon Fibre as micro-reinforcement material and Nano-diamonds and Graphene Oxide as nano-reinforcement material to make PPS composites. The varying mechanical and tribological behaviour of PPS composites with different weight percentage of reinforcement materials was investigated. The optimum composition of the reinforcement materials was identified, which resulted in significant improvement in mechanical and tribological properties of the base material.

Solar thermal energy is emerging as an important source of renewable energy for meeting the ever-increasing energy requirements of the world. Solar selective coatings are known to enhance the efficiency of the photo thermal energy conversion. An ideal solar selective coating has zero reflectance in the solar spectrum region (i.e., 0.3-2.5 µm) and 100% reflectance in the infrared (IR) region (i.e. 2.5-50 µm). In this thesis, novel carbon nanotubes (CNT) and graphene based absorbers have been developed for photo thermal applications. Carbon nanotubes have good optical properties (i.e., α and ε close to 1), high aspect ratios (> 150), high surface area (470 m2/g) and high thermal conductivity (> 3000 W/mK), which enable rapid heat transfer from the CNTs to the substrates. Similarly, graphene also exhibits high transmittance (97%), low reflectance, high thermal conductivity (5000 W/mK) and high oxidation resistance behaviour. The major drawback of using CNTs for photothermal applications is that it exhibits poor spectral selectivity (i.e., α/ε = 1). In other words, it acts as a blackbody absorber. On the other hand, graphene exhibits poor intrinsic absorption behaviour (α - 2.3%) in a broad wavelength range (UV-Near IR). The main objective of the present study is to develop CNT and graphene based absorbers for photothermal conversion applications. The growth of CNT and graphene was carried out using chemical vapour deposition and sputtering techniques. An absorber-reflector tandem concept was used to develop the CNT based tandem absorber (Ti/Al2O3/Co/CNT). The transition from blackbody absorber to solar selective absorber was achieved by varying the CNT thicknesses and by using a suitable underlying absorber (Ti/Al2O3). A simple multilayer heat mirror concept was used to develop the graphene based multilayer absorber (SiO2/graphene/Cu/graphene). The transition from high transmitance to high absorptance was achieved by varying the Cu thickness. The refractive indices and the extinction coefficients of Ti/Al2O3, AlTiO and graphene samples were determined by the phase-modulated spectroscopic ellipsometric technique. Finally, the optical properties (i.e., absorptance and the emittance) of the CNT and graphene based absorbers were investigated. Chapter 1 gives a brief introduction about solar thermal energy, spectrally selective coating and photothermal conversion. The different types of absorbers used to achieve the spectral selectivity have also been discussed shortly. A brief description about the carbon-based materials/allotropes and their properties are outlined. The properties of carbon nanotubes and graphene which are the 1-D and 2-D allotropes of carbon, respectively are tabulated. A detailed literature survey was carried out in order to identify the potential candidates for the photothermal conversion applications. The objectives and the scope of the thesis are also discussed in this chapter. Chapter 2 discusses the deposition and characterization techniques used for the growth and the study of 1-D and 2-D carbon nanostructures. Atmospheric pressure chemical vapour deposition (CVD) and hot filament CVD techniques were used to grow CNT and graphene, respectively. The magnetron sputtering technique was used for the growth of ‘Ti’, ‘Al2O3’ and Co layers which were needed to grow the CNT based tandem absorber on stainless steel (SS) substrates. The important characterization techniques used to examine various properties of the 1-D and 2-D carbon nanostructures include: X-ray diffraction, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), phase modulated ellipsometry, UV-VIS-NIR spectrophotometer, Fourier-infrared spectroscopy (FTIR), micro-Raman spectroscopy and solar spectrum reflectometer and emissometer. Chapter 3 describes the design and development of Ti/Al2O3 coating for the growth of CNT-based tandem absorber on SS substrates. The power densities of the aluminum and titanium targets and the oxygen flow rates were optimized to deposit the Ti/Al2O3 coatings. The optimized Ti/Al2O3 coating with a Co catalyst on top was used as an underlying substrate to grow the CNT-based tandem absorber at 800°C in Ar+H2 atmosphere (i.e., CNT/Co/Al2O3/Ti/SS). The formation of aluminum titanium oxide (AlTiO) was observed during the CNT growth process and this layer enhances the optical properties of the CNT based tandem absorber. The optical constants of Ti, Al2O3 and AlTiO coatings were measured using phase modulated spectroscopic ellipsometry in the wavelength range of 300-900 nm. The experimentally measured ellipsometric parameters have been fitted with the simulated spectra using the Tauc-Lorentz model for generating the dispersion of the optical constants of the Al2O3 and the AlTiO layers. The Ti and Al2O3 layer thicknesses play a major role in the design of the CNT based tandem absorber with good optical properties. Chapter 4 describes the synthesis and characterization of the CNT based tandem absorber (Ti/AlTiO/CoO/CNTs) deposited on SS substrates. CNTs at different thicknesses were grown on Ti/AlTiO/CoO coated SS substrates using atmospheric CVD at various growth durations. The transition from blackbody absorber to solar selective absorber was achieved by varying the thicknesses of the CNTs and by suitably designing the bottom tandem absorber. At thicknesses > 10 µm, the CNT forest acts as near-perfect blackbody absorber, whereas, at thicknesses ≤ 0.36 µm, the IR reflectance of the coating increases (i.e., ε = 0.20) with slight decrease in the absorptance (i.e., α = 0.95). A spectral selectivity (α/ε) of 4.75 has been achieved for the 0.36 µm-thick CNTs grown on SS/Ti/AlTiO/CoO tandem absorber. Chapter 5 discusses the growth of graphene on polycrystalline copper (Cu) foils (1 cm × 1 cm) using hot filament CVD. The roles of the process parameters such as gas flow rates (methane and hydrogen), growth temperatures (filament and substrate) and durations on the growth of graphene were studied. The process parameters were also optimized to grow monolayer, bilayer and multilayer graphene in a controlled manner and the growth mechanism was deduced from the experimental results. The presence of graphene on Cu foils was confirmed using XPS, micro-Raman spectroscopy, FESEM and TEM techniques. The FESEM data clearly confirmed that graphene starts nucleating as hexagonal islands which later evolves into dendritic lobe shaped islands with an increase in the supersaturation. The TEM data substantiated further the growth of monolayer, bilayer and multilayer graphene. The intensity of 2D and G peak ratio (i.e., I2D/IG = 2) confirmed the presence of the monolayer graphene and the absence of the ‘D’ peak in the Raman spectrum indicated the high purity of graphene grown on Cu foils. The results show that the polycrystalline morphology of the copper foil has negligible effect on the growth of monolayer graphene. In Chapter 6, the design and development of graphene/Cu/graphene multilayer absorber and the study of its optical properties are discussed. The multilayer graphene grown on Cu foils has been transferred on quartz and SiO2 substrates in order to fabricate the graphene/Cu/graphene multilayer absorber. The sputtering technique was used to deposit copper on top of graphene/quartz substrates. The uniformity of the transferred multilayer graphene films was confirmed using Raman mapping. A simple multilayer heat mirror concept was used to develop the graphene/Cu/graphene absorber on quartz substrates and the transition from high transmittance to high absorptance was achieved. In order to further enhance the absorption, the graphene/Cu/graphene multilayer coating was fabricated on SiO2 substrates. The thickness of the Cu layer plays a major role in creating destructive interference, which results in high absorptance and low emittance. A high specular absorptance of 0.91 and emittance of 0.22 was achieved for the SiO2 graphene/Cu/graphene multilayer absorber. The specular reflectance of the multilayer absorber coatings was measured using the universal reflectance accessory of the UV-VIS-NIR spectrophotometer. Chapter 7 summarizes the major findings of the present investigation and also suggests future aspects for experimentation and analysis. The results obtained from the present work clearly indicate that both CNT and graphene based absorbers can be used as potential candidates for photothermal applications. In particular, the CNT based tandem absorber can be used for high temperature solar thermal applications and the graphene based multilayer absorber finds applications in the area of photodetectors and optical broadband modulators.

Segmental chain dynamics in polymer blends is a very important topic, not only from a fundamental point of view but also from technological applications. Because of the difficulties in the commercialization of new polymers, industries have turned increasingly towards blending of polymers to optimise their end use (mechanical, rheological) properties. The design of tailor-made materials would be enormously facilitated by the understanding of the blending phenomena at a molecular level. The key question to address is to understand the dynamics of each component of the blend modified by blending? The thesis has systematically studied the effect of multiwalled carbon nanotubes on the chain dynamics, demixing temperature, structural properties and evolution of morphology in a classical miscible polymer blend system (PVDF/PMMA). The thesis comprises of six chapters, Chapter 1 is an introductory chapter that outlines the fundamentals of polymer blends, crystallisation in polymer blends and the basics of dielectric spectroscopy. As one of the rationales of this work is to systematic study whether phase separated in these blends can be used as a tool to develop membrane for water purification. This chapter also gives an overview of the reported studies of ultrafiltration membrane fabrication, factors affecting membrane morphology and flux. In Chapter 2, the materials and methodology used to carry out experiments and the experimental procedures are discussed. Chapter 3 discusses the effect of concentration of PMMA and amine functionalized multiwalled carbon nanotubes (MWNTs) on the crystallisation induced phase separation using FTIR, XRD, POM and shear rheology. Electron microscopy and selective etching confirmed the localisation of MWNTs in the PVDF phase of the blends. Blends with MWNTs facilitated in heterogeneous nucleation manifesting in an increase in crystallisation temperature. The crystallisation induced phase separation in PVDF/PMMA blends was observed to influence the interconnected network of MWNTs in the blends. Chapter 4 discuss the effect of concentration of PMMA and MWNTs on the miscibility and the segmental relaxations was probed in situ by DSC and dielectric relaxation spectroscopy (DRS). The dynamic heterogeneity in the blends as manifested by the presence of an extra relaxation at a higher frequency at or below the crystallisation induced phase separation temperature was also discussed. We found that PVDF/PMMA blend (PVDF ≥ 80 wt%) exhibits three distinct relaxations; αc corresponding to crystalline PVDF, αβ segmental relaxation of PMMA and αm of amorphous miscibility whereas all relaxations overlap and constitute a single broad relaxation in PVDF/PMMA blend (PVDF ≤ 70 wt%). This confirms that there is a certain composition width in this blend wherein three distinct relaxations can be traced. This could due to many reasons like the width of crystal-amorphous interphase in the crystal lamellae, crystal size and morphology is strongly contingent on the concentration of PMMA. Relaxations are not very distinct in presence of MWNTs due to defective spherulites that shift the relaxations towards a higher frequency. Chapter 5 has attempted to tune the microporous morphology of PVDF membranes using crystallisation induced phase separation in PVDF/PMMA blends. As PVDF/PMMA is a melt-miscible blend, the samples were allowed to crystallise and the amorphous PMMA phase, which isolates in the interlamellar or inter-spherulitic regions in the blends, was etched out to generate microporous structures. The pore sizes can be tuned by varying the PMMA concentration in the blends. We observed that 60/40 PVDF/PMMA blends showed larger pores as compared to 90/10 PVDF/PMMA blends. We further modified PVDF membranes by sputtering silver on the surface. The bacterial cell viability was distinctly suppressed (99 %) in silver sputtered membranes. The ICP analysis suggests that slow Ag+ ions release from the sputtered membrane surface assisted in developing antibacterial surface. Our findings open new avenues in designing water filtration membranes and also help in understanding the crystallisation kinetics for tuning pore size in membranes. Chapter 6 summarises the important results of this work. MWNTs act as hetero nucleating agent and specifically interact with PVDF thereby influences the dynamics of PVDF chains. MWNTs can also restrict the amorphous segmental mobility and can influence the intermolecular cooperativity and coupling. The crystallisation induced phase separation in various blends can result in various crystalline morphologies depending on the PVDF concentration. By selectively etching PMMA from the phase-separated blends, microporous morphology can be generated

The growing incidences of orthopedic problems globally have created a huge demand for strong bioactive materials for bone tissue engineering. Over the years, studies have shown chemical, physical, and mechanical properties of biomaterials influence the cellular interactions at the material-tissue interface, which subsequently controls biological response to materials. Strong biomaterials with surface properties that actively direct cellular response hold the key for engineering the next generation orthopedic implants. With its unique properties graphene can be used to reinforce poly (ε-caprolactone) (PCL) to prepare strong and bioactive polymer nanocomposites for bone tissue regeneration. The thesis entitled ―Engineering bioactive and multifunctional graphene polymer composites for bone tissue regeneration” systematically studies the effect of different chemically functionalized and metal-graphene hybrid nanoparticles in PCL composites for bone tissue engineering. The thesis comprises of seven chapters. Chapter 1 is an outline review on the impact of graphene and graphene derived particles to prepare supporting substrates for tissue regeneration and the associated cell response to multifunctional graphene substrate. This chapter discusses how cells interact with different graphene based particles and the interplay between cells performance and multifunctional properties of graphene based substrates. Chapter 2 describes the role, if any, of the functionalization of graphene on mechanical properties, stem cell response and bacterial biofilm formation. PCL composites of graphene oxide (GO), reduced GO (RGO) and amine-functionalized GO (AGO) were prepared at different filler contents (1%, 3% and 5%). Although the addition of the nanoparticles to PCL markedly increased the storage modulus, this increase was higher for GO and AGO than with RGO. In vitro cell studies revealed that the AGO and GO particles significantly increased human mesenchymal stem cell (hMSC) proliferation. AGO was most effective in augmenting stem cell osteogenesis leading to mineralization. Bacterial studies revealed that interaction with functionalized GO induced bacterial cell death due to membrane damage which was further accentuated by amine groups in AGO. The synergistic effect of oxygen containing functional groups and amine groups on AGO-reinforced composites renders the optimal combination of improved modulus, favorable stem cell response and biofilm inhibition desired for orthopaedic applications. In Chapter 3, toward preparing strong multi-biofunctional materials, poly(ethylenimine) (PEI) conjugated graphene oxide (GO_PEI) was synthesized using poly(acrylic acid) (PAA) as spacer and incorporated in PCL at different fractions. GO_PEI significantly promoted proliferation and formation of focal adhesions in hMSCs on PCL. GO_PEI was highly potent in inducing stem cell osteogenesis leading to 90% increase in alkaline phosphatase activity and mineralization over neat PCL with 5% filler content and was 50% better than GO. Remarkably, 5% GO_PEI was as potent as soluble osteo-inductive factors. Increased adsorption of osteogenic factors due to the amine and oxygen containing functional groups on GO_PEI augment stem cell differentiation. GO_PEI was also highly efficient in imparting bactericidal activity with 85% reduction in counts of E. coli colonies compared to neat PCL at 5% filler content and was more than twice as efficient as GO. This may be attributed to the synergistic effect of the sharp edges of the particles along with the presence of the different chemical moieties. Thus, in contrast to using labile biomolecules, GO_PEI based polymer composites can be utilized to prepare bioactive resorbable biomaterials for fabricating orthopedic devices for fracture fixation and tissue engineering. Chapter 4 describes the preparation of hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and its advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) nanoparticles were synthesized by facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200 – 300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared incorporating RGO_Sr particles in PCL. The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare scaffolds with osteoinductive property. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Chapter 5 discusses the use of hybrid graphene-silver particles (RGO_Ag) to reinforce PCL and compared with PCL/RGO and PCL/Ag composites containing RGO and silver nanoparticles (AgNPs), respectively. RGO_Ag hybrid particles were well dispersed in the PCL matrix unlike the RGO and AgNPs due to enhanced exfoliation. RGO_Ag led to 77 % increase in the modulus of PCL and provided a conductive network for electron transfer. Electrical conductivity increased four orders of magnitude from 10-11 S/cm to 10-7 S/cm at 5 wt % filler that greatly exceeded the improvements with the use of RGO and AgNP in PCL. RGO_Ag particles reinforced in PCL showed sustained release of silver ions from the PCL matrix unlike the burst release from PCL/Ag. PCL/RGO_Ag and PCL/RGO composites were non-toxic to hMSCs and supported osteogenic differentiation unlike the PCL/Ag composites which were highly toxic at ≥3% filler content. The PCL/RGO_Ag composites exhibited good antibacterial effect due to a combination of silver ion release from the AgNPs and the mechanical rupture induced by the RGO in the hybrid nanoparticles. Thus, the synergistic effect of Ag and RGO in the PCL matrix uniquely yielded a multifunctional material for use in implantable biomedical devices and tissue engineering. Chapter 6 presents investigation of potential differences in the biological response to graphene in polymer composites in the form of 2D substrates and 3D scaffolds. Results showed that osteoblast response to graphene in polymer nanocomposites is markedly altered between 2D substrates and 3D scaffold due to the roughness induced by the sharp edges of graphene at the surface in 3D but not in 2D. Osteoblast organized into aggregates in 3D scaffolds in contrast to more well spread and randomly distributed cells on 2D discs due to the macro-porous architecture of the scaffolds. Increased cell-cell contact and altered cellular morphology led to significantly higher mineralization in 3D scaffolds compared to 2D. This study demonstrates that the cellular response to nanoparticles in composites can change markedly by varying the processing route. Chapter 7 summarizes the important results and future directions of the work. This chapter provides general conclusions arising from this study, and makes suggestions for future work designed to provide a greater understanding of the in vivo response in terms of bio-distribution of the released functionalized graphene from the scaffold or substrate must be assessed with special attention on their accumulation or excretion.

This work deals with issues of application of the graphene material in the field of electrochemical energy storage. It includes basic graphene properties, the overview of methods for the production of lithium-iron-phosphate/graphene composites and results of different research approaches. The general aim is to present growing opportunity of application of graphene based composites in the electrochemical energy storage field. In the experimental part of this work, a electrochemical exfoliation of graphite and a production of LFP/G composites with different amount of graphene material and with different types of graphene material are carried out. This work includes also x-ray diffraction spectroscopy measurements and the evaluation of impacts of graphene additives on final properties of the electrochemical energy storage.

No description available.

This master thesis deals with the topic of alternative production of hydrogen as the energy carrier of the future. The primary focus is on the production of hydrogen based on photocatalytical water splitting in the presence of semiconductor materials (especially modified and unmodified TiO2). The aim of the thesis is a synthesis of nanostructured oxide, graphene/graphene oxide particles and its composites, and a study of its structures and photocatalytical properties regarding photolysis of water. Products of the syntheses are described from the point of view of phase composition, surface area and photocatalytical activity. The main output of the thesis is a discussion of the influence of alkaline complex forming reagents on the hydrothermal low-temperature synthesis of biphasic TiO2, and a study of the influence of graphene/graphene oxide modification on photocatalytical activity of biphasic TiO2.

This master´s thesis is focused on measurement of optical properties of thin layer of materials used in organic solar cells (OSC). The usage of graphene oxides and its reduced forms as parts of hole transport layer (HLT) in OSC were studied. At the beginning of the thesis, there is described basic theory necessary to understand the optical properties of thin layers. The thin layer deposition and reduction of GO are discussed too. The experimental part is aimed to the optical characterization of prepared thin films. The results from optical microscopy, UV-VIS spectroscopy, FT-IR spectroscopy and spectroscopic ellipsometry were obtained. At the end of the thesis, the results are concluded and compared with already published literature.

Indiana University-Purdue University Indianapolis (IUPUI) / The innovation and investigation of catalysts in proton exchange membrane fuel cells are included in this thesis. In the first part of this work, stability of the catalyst support of PEMFC catalyst is investigated. Nanoscale platinum particles were loaded on two different kinds of carbon supports, nano graphene sheets and functionalized carbon black/graphene hybrid were developed by the liquid phase reaction. The crystal structure of two kinds of catalysts was characterized by X-ray diffractometer (XRD). The morphology and particle size were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). Pt loading was measured by thermal gravimetric analysis (TGA). The Brunauer, Emmett and Teller (BET) method was applied to test the surface area of the catalysts. The electrochemical surface area (ECSA) and mass activity during oxygen reduction reaction (ORR) process for two kinds of catalyst were tested by cyclic voltammetry method under different conditions. The stability of the catalysts were tested by accelerated durability test (ADT). The results show that although the mass activity of Pt/graphene is much lower, the stability of it is much better than that of the commercial catalyst. After adding functionalized carbon black (FCB) as spacer, the stability of the catalyst is preserved and at the meantime, the mass activity becomes higher than 20% Pt/XC72 catalyst. The lower mass activity of both catalysts are due to the limitation of the electrolyte diffusion into the carbon support because of the aggregation nature of graphene nano-sheets. After introducing functional carbon black as spacer, the mass activity and ECSA increased dramatically which proved that FCB can be applied to prevent the restacking of graphene and hence solved the diffusion problem. In the meantime, the durability was still keeping the same as Pt/graphene catalyst. In the second part of the work, the restacking problem was solved by introducing FCB as spacers between functionalized graphene nanosheets. The same measurement was applied to test the electrochemical performance of Pt/FCB/FG catalyst. The new catalyst showed a higher mass activity compared to Pt/graphene catalyst which meant the restacking problem was partially solved. The durability of the Pt/FCB/FG catalyst was still excellent.